F-117 Nighthawk

The F-117 Nighthawk was a stealth attack aircraft used by the US Air Force during the Persian Gulf War, Operation Enduring Freedom, and Operation Iraqi Freedom. The Nighthawk was developed and manufactured by Lockheed and the prototype, the YF-117A, made its first flight on June 18, 1981, entering service with the United States Air Force on October 15, 1983. By July 1990, 59 production F-117s had been delivered to the American Air Force. The Air Force had always denied the existence of this aircraft until 1988, when a grainy photograph was released to the public. In April 1990 two were flown into Nellis Air Force Base, Nevada, arriving during daylight and visible to a crowd of tens of thousands.

The F-117 was conceived out of the combat experience in the Vietnam War when increasingly sophisticated Soviet surface-to-air missiles, like the SAM, downed heavy bombers and attack aircraft. It was a black project, an ultra-secret program for much of its life, until the late 1980s. The project began in 1975 with a model called the "Hopeless Diamond," which was a wordplay on the Hope Diamond due to its appearance. In 1977 Lockheed produced two 60% scale models under the Have Blue contract. The Have Blue program was a stealth technology demonstrator that lasted from 1976 to 1979. The success of Have Blue led the Air Force to create the Senior Trend program which developed the F-117.

The F-117 was designed to deflect radar signals and was about the size of an F-15 Eagle. The single-seat Nighthawk was powered by two non-afterburning General Electric F404 turbofan engines, and was fitted with quadruple-redundant fly-by-wire flight controls. The Nighthawk was air refuelable. The Lockheed F-117 was limited to subsonic speeds, due to losses in the inlet and outlet, a very low wing aspect ratio, a high sweep angle (50°) needed to deflect incoming radar waves to the sides, and no afterburner. The F-117A was fitted out with sophisticated navigation and attack systems integrated into a digital avionics suite. It carried no radar, which lowers emissions and cross-section, and navigated mainly by GPS and high-accuracy inertial navigation. Missions were coordinated by an automated planning system which could automatically perform all aspects of an attack mission.

The F-117 was withdrawn from front line service on April 22, 2008, due to the fielding of the F-22 Raptor and the impending fielding of the F-35 Lightning II, both of which are stealth and supersonic.